Metal complexes of sulphur ligands. Part 13. Reaction of dichloro-(η-cyclo-octa-1,5-diene)-palladium and -platinum complexes with some sulphur-containing nucleophiles

Abstract

Reaction of [Pd(C₈H₁₂)Cl₂](C₈H₁₂= cyclo-octa-1,5-diene) with equimolar amounts of various alkali-metal dithioacid salts ([S–S^–]=[S₂NEt₂]^–, [S₂COEt]^–, or [S₂PMe₂]^–) gives the chloride-bridged dimers[{PdCl(S–S)}₂](1). Metathetical reactions of these give the corresponding [{PdX(S₂CNEt₂)}₂](X = Br^– or [SPh]^–).· Cleavage of these complexes with Lewis bases gives [PdCl(S–S)L](2: L = PPh₃, [S–S^–]=[S₂CNEt₂]^–, [S₂COEt]^–, or [S₂PMe₂]^–; L = AsPh₃, SbPh₃, or C₅H₅N, [S–S^–]=[S₂CNEt₂]^–), and with M′Cl–HCl, M′[PdCl₂(S₂CNEt₂)](3; M′=[AsPh₄]⁺ or [PPh₃(CH₂Ph)]⁺) are formed. Reaction of (1; [S–S]^–=[S₂CNEt₂]^–) with Na[S₂PMe₂]·2H₂O gives [Pd(S₂CNEt₂)(S₂PMe₂)](4a) which partially disproportionates in solution to [Pd(S₂CNEt₂)₂] and [Pd(S₂PMe₂)₂]. Complex (4a) reacts with PPh₃ to give [Pd(PPh₃)(S₂CNEt₂)(S₂PMe₂)](5a) which possesses bidentate [S₂CNEt₂]^– and unidentate [S₂PMe₂]^– groups. In contrast, reaction of [Pt(C₈H₁₂)Cl₂] and Na[S₂CNEt₂]·3H₂O (1: 1 mol ratio) gives [{PtCl(S₂CNEt₂)}₂C₈H₁₂](6a) which in turn reacts with PPh₃, to give [PtCl(PPh₃)(S₂CNEt₂)] and with excess of PPh₃, to give [Pt(PPh₃)₂(S₂CNEt₂)]Cl·H₂O. Reaction of (6a) and Na[S₂PMe₂]·2H₂O gives [Pt(S₂CNEt₂)(S₂PMe₂)](4b) which on treatment with PPh₃ gives [Pt(PPh₃)(S₂CNEt₂)(S₂PMe₂)](5b).